1990497601 has 4 divisors (see below), whose sum is σ = 1993854852. Its totient is φ = 1987140352.

The previous prime is 1990497571. The next prime is 1990497637. The reversal of 1990497601 is 1067940991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1730643201 + 259854400 = 41601^2 + 16120^2 .

It is a cyclic number.

It is not a de Polignac number, because 1990497601 - 2¹⁷ = 1990366529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1990497401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1677736 + ... + 1678921.

It is an arithmetic number, because the mean of its divisors is an integer number (498463713).

Almost surely, 2^1990497601 is an apocalyptic number.

It is an amenable number.

1990497601 is a deficient number, since it is larger than the sum of its proper divisors (3357251).

1990497601 is an equidigital number, since it uses as much as digits as its factorization.

1990497601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3357250.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 1990497601 is about 44614.9930068357. The cubic root of 1990497601 is about 1257.9225026254.

The spelling of 1990497601 in words is "one billion, nine hundred ninety million, four hundred ninety-seven thousand, six hundred one".